<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>flex</title>
<style>
/* 布局1-flex */
.box1{ display: flex;}
.box1 .side-l{ width: 200px;}
.box1 .side-c{ flex: 1;}
.box1 .side-r{ width: 200px;}
</style>
</head>
<body>
<!-- 布局1-flex -->
<div class="box1">
	<div class="side-l">11</div>
	<div class="side-c">
		<div>22</div>
		<div>33</div>
	</div>
	<div class="side-r">44</div>
</div>
</body>
</html>